131I-FAPI

131I-FAPI is an **experimental radiopharmaceutical** comprised of fibroblast activation protein inhibitor (FAPI) molecules structurally modified to be labeled with radioactive iodine-131. It selectively targets the **fibroblast activation protein (FAP)**, which is highly expressed in the tumor stroma of most malignant epithelial cancers and low in normal tissues. By combining FAPI’s affinity for FAP with the cytotoxic β and γ emissions of iodine-131, 131I-FAPI delivers targeted radiotherapy to cancer-associated fibroblasts within tumors. In preclinical studies, such as those using human glioma cells (U87), 131I-FAPI exhibits high stability, strong hydrophilicity, specific binding, and inhibition of cancer cell proliferation and migration. The primary mechanism is targeted cell killing via radioligand binding to FAP+ tissues. The drug shows promise for tumor-targeted therapy and imaging (theranostics), especially for cancers with abundant cancer-associated fibroblasts. Current development emphasizes evaluation in preclinical models, with select studies reporting tumor growth suppression in mouse xenograft models[1][2][3][4].

Other names

131I-FAPIiodine-131 labeled fibroblast activation protein inhibitoriodine131 labeled fibroblast activation protein inhibitoriodine 131 labeled fibroblast activation protein inhibitor